1. Field of the Invention
The present invention relates to a numerical controller, and particularly to a numerical controller that performs fixed cycle operation control of nicking in order to shred chips.
2. Description of the Related Art
Conventionally, there is a technique relating to boring machining in which a groove is machined in the axial direction in a part of allowance of boring in advance using a bar cutter having a smaller diameter than a boring diameter so as to prevent generation of long chips as illustrated in FIG. 11 (for example, JP H04-360704 A).
The technique disclosed in JP H04-360704 A is limited to the boring machining, and there is no comment regarding other machining methods, for example, turning. When the technique disclosed in JP H04-360704 A is applied to the turning, it is possible to conceive a method of machining an axial groove illustrated in FIG. 12, for example. When the axial groove illustrated in FIG. 12 is machined in a workpiece to be subjected to the turning, it is necessary to stop rotation of the workpiece first, and then, perform the machining in a separate step using a drilling tool. However, the machining is not the turning, and thus, there is a problem that the machining procedure becomes complicated. In addition, it is also possible performing the machining by preparing a machine such as a machining center in addition to a machining machine to perform the turning, but there is a problem that cost increases because it is necessary to prepare the two machines.